1. Technical Field
The present invention is directed toward windows, and more particularly to tilt latches and sash locks for sliding or double/single-hung windows.
2. Background Art
Double/single-hung windows include two window sashes typically mounted for vertical movement along adjacent parallel tracks. Traditional double/single-hung window designs provide poor washability, because it is difficult for a person located inside the room to wash the outside of the window pane. To fully wash the outer surface of such windows (which outer surface is the one which is most often in need of cleaning), the person cleaning the window must typically go outside the dwelling. This is not only extremely inconvenient (as the person has to walk significant distances merely to wash both sides of a single window), it can also force a window washer, when trying to wash double/single-hung windows located at significant heights, to face the undesirable choice of either risking injury by climbing to that height or doing a relatively poor job of washing by merely reaching from a distance with a hose or a special long pole apparatus of some type. Such cleaning is still further complicated where there are screens or storm windows which must be removed prior to washing.
To overcome this problem, tilting latches for these types of windows have sometimes been provided. Such latches have generally been installed in opposite ends of a top horizontal rail of the upper and/or lower sash, and typically include a tongue or plunger which during normal operation extends out from the side of the sash into the sash track in the window frame to guide the sash for typical vertical movement. The tongue or plunger of each latch is retracted in some manner when washing is desired to free the top rail of the sash from the track so that the sash may be suitably pivoted inwardly about pivots guiding the bottom rail of the sash in the track and thereby allow the washer to easily reach the outside surface of the window pane of that sash.
The tongue or plunger in many of the prior art latches is commonly biased outwardly into the track by a spring structure or the like, with the tongue retracted inwardly by the washer manually pulling the tongues in toward the center of the top rail against the force of the spring (see, for example, U.S. Pat. No. 5,139,291). However, with such structures, the tongues can be difficult to move. Such problems can cause the person trying to retract the tongues to hurt their hands and, if the tongue is too difficult to move, they may just give up on trying to wash the window entirely and thereby lose the advantage of the latch structure completely.
Further, such tilt latches have typically had an assortment of complex structures which are difficult and time consuming (and therefore costly) to assemble.
Some attempts have also been made to control movement of the tongues by a pivoting lever or handle, occasionally functioning in combination with the sash lock (see, for example, U.S. Pat. Nos. 5,090,750 and 5,398,447). While this can aid in retracting the tongue, such latches have nevertheless encountered many of the above described problems (e.g., difficult, time consuming and costly to assemble, inadequately resistant to damage, and susceptible to allowing the window sash to inadvertently be inadequately secured to the track). Further, latches of this type, particularly those in which both sash locking and tilt latching are controlled, can have difficulty providing smooth, consistent and reliable operation over their long expected useful life. Still further, latches of this type can be difficult to install, as they typically require precise positioning in order to ensure that the tongues are retracted equally as required for proper operation. Also, such latches commonly also require that they be centrally positioned on the sash to ensure equal retraction, thereby making use of such latches in large window requiring multiple locks problematic. Additionally, even if properly installed initially, events occurring over the long expected life of such products (for example, slight slipping in connections or tensile distortion of components) can cause such latches to thereafter not function properly.
The present invention is directed toward overcoming one or more of the problems set forth above.